Process for preparing powdery starch sugars

ABSTRACT

A process for producing starch sugars involves subjecting starch slurries to the action of acids or combinations of various amylases and converting dextrins, produced by saccharification of starch, into straight-chain malt dextrins using an Alpha -1,6glucosidase that decomposes the Alpha -1,6-glucoside bonds, or the branching bonds of starch, thereby facilitating the saccharifying reaction and, at the same time, converting the oligosaccharides or dextrins into straight-chain malt dextrins or oligosaccharides, and thereby preparing a starch sugar solution of a composition different from that of ordinary starch syrups and which is less viscous, and then finishing the liquor easily by spray drying to a powdery product.

United States Patent 1191 Kurimoto et al. [4 1 Jan. 30, 1973 1541PROCESS FOR PREPARING POWDERY 3,236,687 2/1966 Smith etal. ..127/5sSTARCH SUGARS 2,900,256 8/1959 Scott ..159 48 [751 Inventors: M .111610, Okayam hh 312321323 13533 h'e'fififtffffiiliiiii... iijijiililiMamorll Hiram k y both f 3.560345 2/1971 Yokobayashietal. ..195/31 RJapan [73] Assignee: Harashibara Company, Okayama- Primary Examiner-ALOUiS M n ell Shi, OkayamaJapan Assistant Examiner-Gary M. Nath [22]Filed: No 19, 9 Attorney-Browdy and Neimark 1 PP 51 ABSTRACT A rocessfor roducin starch su ars involves sub- [30] Forelgn Apphcfltlon PrimtyData jecFing starch sfurries to the action of acids or com- 1968 Japan"43/85844 binations of various amylases and converting dextrins, [52][1.8. CI. ..l95/3l R produced by saccharification of starch, intostraight- [51] lnt.Cl. ..C12b 1/00 chain malt dextrins using ana-l,6-glucosidase that [58] Field of Search ..i95/3l; 99/142, I99, 203;decomposes the a-l,6-glucoside bonds, or the 127/43, 30,29, 58, 61;159/4, 8, 48 branching bonds of starch, thereby facilitating thesaccharifying reaction and, at the same time, convert- [56] ReferencesCited ing the oligosaccharides or dextrins into straight-chain maltdextrins or oligosaccharides, and thereby prepar- UNITED STATES PATENTSing a starch sugar solution of a composition different 3,535,123 10/1970Heady ..195/31 from that of rdhlary Starch Syrups and which is less2,728,673 12/1955 viscous, and then finishing the liquor easily by spray3,565,765 2/1971 drying to a powdery P 3,5l9,054 7/l970 Cauathaio et al..l59/48 R 6 Claims, N0 Drawings PROCESS FOR PREPARING POWDERY STARCHSUGARS This invention relates to a process for producing starch sugarsby subjecting starch slurries to the action of acids or combinations ofvarious amylases and converting dextrins, produced by saccharificationof starch, into straight-chain malt dextrins using an a-1,6- glucosidasethat decomposes the a-l,6-glucoside bonds, or the branching bonds ofstarch, thereby facilitating the saccharifying reaction and, at the sametime, converting the oligosaccharides or dextrins into straight-chainmalt dextrins or oligosaccharides, and thereby preparing a starch sugarsolution of a composition different from that of ordinary starch syrupsand which is less viscous, and then finishing the liquor easily by spraydrying to a powdery product.

Ordinary acid-converted starch syrups of low saccharification degreescontain high proportions of dextrins of branched structures havingrelatively high molecular weights and therefore they are too viscous forsmooth filtration and ion exchangeprocesses of purification. The highviscosity also renders spray drying difficult. It is for this reasonthat those syrups are usually subjected to spray drying in lowconcentrations, e.g., of about 60 percent.

On the other hand, it is possible, in accordance with the presentinvention, to produce starch syrups free from branched dextrins andhence of lower viscosity than ordinary acidor enzyme-converted starchsyrups of the same D.E. values, by taking advantage of thecharacteristic of the a-l,6-glucosidase developed by the presentinventors to decompose selectively the al,6-glucoside bonds whichrepresent the branching bonds in a starch molecule, and eitherdecomposing gelatinized starch thereby first into straight chainamylose,thus enabling B-amylase to act fully, or by using the a-1,6-glucosidasein the course of saccharification of starch with various amylases,thereby converting the dextrins of the resulting starch syrup intostraight-chain malt dextrins.

For the reasons stated above, the use of a-l,6-glucosidase with variousamylases is not only useful in reducing the viscosity of products but inproducing starch syrups whose compositions are controllable withcomparative ease, including the production of those syrups composed of apreponderance of maltose and a minor proportion of glucose, or forsyrups which comprise major proportions of glucose, or for syrups whichconsist essentially of oligosaccharides.

Thus, the starch syrups or starch sugars obtained through theutilization of 11-1 ,c-glucosidase are allowed to have freely chosen,unusual sugar compositions and, in addition, considering their dextrinstructures, they have less viscosity than ordinary starch syrups of thesame D.E. values, and thereforethe spray drying of the sugar solution iseasily accomplished.

As already stated, the conventionally prepared highviscosity starchsyrups with low D.E. values present difficulties in being spray driedunless they are diluted to concentrations lower than 60 percent. Thestarch syrups obtained in accordance with the present process, bycontrast, generally exhibit such low viscosity that they are sprayedwith extreme case in concentrations ranging from 70 to 80 percentthrough high pressure nozzles using pressures of I to 150 kg/cm.

The starch syrups which are produced from starch slurries usingcombinations of various amylases and a- 1,6-glucosidases and the methodof saccharification according to the present invention are illustratedby the following examples. The a-l,6-glucosidases used were obtained forthe purpose of the invention from various type cultures or from usefulstrains chosen from among the strains separated from soils in variouslocations. To cite a few examples, they included the enzymes produced bythe bacteria of the genera Escherichia (ATCC 21073), Pseudomonas (ATCC21262), Lactobacillus (ATCC 8008), Micrococous (lFO 3345), Nocardia (IFO3384) and Aerobacter (ATCC 8724), which are described in detail,respectively, in the specifications of U.S. Pat. applications Ser. Nos.749,288, 733,326 now patent 3,560,345, and 810,293 now abandoned.Culture fluids of these strains were filtered, and the clarifiedsolutions so obtained were used as enzyme solutions.

Using these a-l,6-glucosidases and amylases, sugar solutions of desiredsugar compositions, sweetness, and viscosity were prepared. Thesesolutions were purified, concentrated, and then subjected to spraydrying. For spray drying, the drying column described in thespecification of Japanese Pat. Publication No. 7076/1969 was employed.Into a parallel flow of hot air, each sugar solution was sprayed bymeans of triple high-pressure pumps at pressure ranging from 150 to 100kg/cm Further particulars will be given in the following description ofexamples.

Pulverization of the sugar solutions may be accomplished by a vacuumdrying technique as well. Experimentally, each sugar solution in aconcentration of percent heated with steam at 5 kg/cm was extruded intoa vacuum of --700 mm for drying, and the dried product was pulverized toa powdery state. The apparent specific gravity of the product obtainedby this technique was quite low.

The following examples are described as employing the spray dryingtechnique alone.

EXAMPLES Raw material starches used were those of corn, white potato,sweet potato, wheat, sago, and also highamylose starch, etc. Each starchwas first purified and treated to prepare a starch slurry having aconcentration of 30 to 40 percent. For the liquefaction andgelatinization, a continuous liquefying equipment was used. Since thesaccharification needs a lengthy period of time, a batch-typesaccharification tank was provided for that purpose.

To begin with, the starch slurry was adjusted to pH 5.0, pumped into thecontinuous liquefier equipped with an agitator and, while beingvigorously agitated, the charge was suitably liquefied or gelatinized.For example, it was either rapidly gelatinized by heating to 160 C withthe supply of live steam or was liquefied by heating to about C,following the addition of aamylase. Next, the starch, liquefied to asuitable D.E. value, was rapidly cooled to a temperature and adjusted toa pH both suitable for the enzyme to be subsequently introduced. Theliquefied starch was either subjected to the action of ana-1,6-glucosidase for decomposition of the branched structure of thestarchlike amylopectin to straight-chain malt dextrins which in turnwere decomposed with the addition ofa suitable conditions forsaccharification and spray drying were saccharogenic amylase; or theliquefied starch was subas tabled below.

mam? 1 l'lxmnplunumber I ll 11] IV V VI VII st rch Hweotpotnto" Com"Corn llighnmylaso lotnto. 8ngo (Jasmivn. Concentration,percent 40 35 3580 40 85 40. Liquefaction:

Enzymeorncid,unit/g. starch None None.... Oxalicecidml! 3.5....Oxalieacid,pH 4.. 010.. C15. (115 Temperature, C 163 185 120 160 9O I).E2 6 2.0 3.0 3.0 2 85. lstsaceharlficatlon:

Enzyme, u./g L30 Lglio L-R2 B10 P-B5. 05 P30.

IIeImpcrature, C

liordiae',r;::::::: 2nd saccharlfication'.

Enzyme, u./g C20 C20..." C20 I20 P20 Iso- Temperature, C

Original liquid concentrnt ion, percent...

\lt/irlmnpog'attlru, 1.... V..-

.TT: (1)6? 0 7.... 1 U... 0 5 (1)62. J "011 Main oiiipgiiofi tsffjfMultosn. Glucose,multdextrin. Multoso,ll0%. Mnltosimnnltdux- Mullt.

i ll (3X- trin, glucose,

ructoso.

aAmylase :(C) commercially available liquefying enzyme.

B-Amylase :(B) extracted from wheat bran.

Gluc-amylase(Rhlzpous) :(R).

Aerobacter pullulanase (P) Pseudomonas enzyme :(I)

Lactobaelllus enzyme :(L).

jected to the action of a suitable saccharogenic amylase What is claimedis: for decomposition and then, with the addition of the a- A grow {6,producing Special powdery f 1,6-glucosrdase, the brancheddex were decom'sugars of various compositions from starch slurries Posed to dextrms' Byf' h f Starch comprising liquefying said starch slurry to a D. E. of y phaving a desired composition and 2-3; subjecting said liquefied starchto the action of a- ?weemess was prepa red' T f' and 1,6-glucosidaseproduced from the bacteria of the time for the lamy(l1olysis variedaccording to the type of genus Lactobacillus (ATCC 8008), therebypreparing enzyme emp Dye a sugar solution ofa low viscosity having acomposition The s'flcchanfied Solutlon thus m a heated 40 principally ofmalt dextrins free from branched structo deact'vate the enzymesdecolored ture and, to lesser extents, of other sugars; adjusting thecoal and fufther and F F concentration to 70-80 percent; and then dryingthe exchange resins. Followlng the purification, the soluhighlyconcentrated solution by spray drying through tion was concentrated. Theresulting solution, which nozzlesusingapressureof ]0O 15okg/cmz was lessviscous than ordinary acid-converted starch syrups and starch sugars ofthe same D.E. values, was further concentrated to a high concentrationof 70 to 80 percent, and then spray dried.

2 A process for preparing powdery starch sugars according to claim 1wherein said spray drying step is accomplished by spraying into airheated to 80-l50 C. in the upper part of the drying chamber, collectingthe The spray dryer was a cylindrical column having an effective heightof more than 10 meters. From a high gi f s iiz lai 5:3 g zzzi i rpressure nozzle mounted on the top of the column, the yg g g ggpermeable bed g concentrated sugar solution was sprayed. The hot dryvM- ing was Supplied as a downward flow from the top of 3. A process inaccordance w th claim 1 wherein said the drying column. The airtemperature used ranged starch ls 'f f by a techmque selecged from Pfrom 80 to 150 C. The powdery starch sugars dried in fonslstmg heat,mgto about 160 treatmg this way were collected on a moving bed of wirescreen and treatmg i fl stretched in the lower part of the column andthe mass A Process in accordance with claim 3 wherein Said was cooled bycold air introduced from below the movliquefied starch is Subjected in aseparate Stage to the ing The powdery product on the moving bed wasaction, of an enzyme other than a-l,6-glucosidase, said continuouslytaken out of the column, collected in a other enlymg bemg Selected fromthe group consisting hopper, sieved, and packed in a bag without beingexof 'amylasa, I my s A posed to the atmo heri ir d h idit Th d 5. Aprocess in accordance with claim 4 wherein said products obtained in themanner described were powaction of a-l,6-gll100SidaSe is cte in a firststage defy products f ll l b l Shape h i water along with glucoamylase,followed by treatment with contents of one to three percent and wereeasy to han- Said y in Said separate stagedle, though the moistureabsorption varied according 6. A pm'ee's'srei'pmduciagiawaerystarchsugars of to the degree of saccharification or D.E. attained. Thevarious compositions, which comprises liquefying a isomerase, addingthereto a-l,6-glucosidase produced 5 by the bacteria of the genusLactobacillus (ATCC 8008) during the initial or middle stage of theprevious saccharification; purifying and concentrating the saccharifiedsolution; and then drying the concentrated solution by spray drying at ahigh pressure.

1. A process for producing special powdery starch sugars of variouscompositions from starch slurries comprising liquefying said starchslurry to a D. E. of 2-3; subjecting said liquefied starch to the actionof Alpha -1,6-glucosidase produced from the bacteria of the genusLactobacillus (ATCC 8008), thereby preparing a sugar solution of a lowviscosity having a composition principally of malt dextrins free frombranched structure and, to lesser extents, of other sugars; adjustingthe concentration to 70-80 percent; and then drying the highlyconcentrated solution by spray drying through nozzles using a pressureof 100-150 kg/cm2.
 2. A process for preparing powdery starch sugarsaccording to claim 1 wherein said spray drying step is accomplished byspraying into air heated to 80*-150* C. in the upper part of the dryingchamber, collecting the resulting powder on a gas-permeable moving bedin the lower part, and passing a stream of cooling air upwardly throughsaid gas-permeable bed.
 3. A process in accordance with claim 1 whereinsaid starch is liquefied by a technique selected from the groupconsisting of heating to about 160* C., treating with acid, and treatingwith Alpha -amylase.
 4. A process in accordance with claim 3 whereinsaid liquefied starch is subjected in a separate stage to the action, ofan enzyme other than Alpha -1,6-glucosidase, said other enzyme beingselected from the group consistiNg of Alpha -amylase, Beta -amylase andisomerase.
 5. A process in accordance with claim 4 wherein said actionof Alpha -1,6-glucosidase is effected in a first stage along withglucoamylase, followed by treatment with said Alpha -amylase in saidseparate stage.